Little Siblings Raise Your Blood Pressure

Does your little brother really stress you out? Even into adulthood, does he just make your blood boil?

Well, you're not alone. A new study of Bolivian adults has shown that having a younger sibling isn't just a pain when you're a kid, it may also raise your blood pressure into adulthood.

Researchers do not have enough data to conclude that higher blood pressure is directly caused by having a younger sibling; they can only show that there is a correlation between the two. However, they do proffer a possible reason as to why: younger siblings — especially little brothers — take parental attention from older children while burdening the older kids with extra responsibility.

The findings, detailed this month in the journal Economics and Human Biology, do suggest that younger brothers seemed to bring the bigger health risk: Adults with younger brothers had blood pressures up to 6 percent higher than others in the study. Younger sisters were also a problem, but only for older girls, whose blood pressure increased by 3.8 percent for each younger sister.

For the study, researchers measured the blood pressure of 374 adults living in 13 Bolivian villages in the Amazon, many from large families. The research team found that having younger kids in the family may have drained parental attention as their older siblings were forced to pick up some of the parenting workload. And looking out for the younger siblings requires a lot of work from elder children.

In wealthier, well-developed countries like America, the same effect may not play out, researchers said. Meaning you might have to blame your high blood pressure on someone else.

Do your siblings make you hot under the collar? Let us know in the comments.